1. Field of the Invention
This invention is concerned generally with parting tools having a heating element for heating the workpiece to be parted, and is more particularly concerned with parting tools of the type required for heating and melting the mastic or mastic-like material utilized around the edges of automotive vehicular windshields, and wherein the mastic effects a waterproofing seal between the windshield and the body of the vehicle.
2. Description of the Prior Art
Parting tools for assisting in the removal of automobile windshields are known in which a shaped knife is utilized to break the seal of the rubber or other mastic, exterior means being employed to heat the knife for the purpose of softening and melting the sealant. To this end it has been common in the prior art to employ a knife having a portion in heat transfer contact with a heater assembly.
In one such embodiment the tool is provided with a handle and end members separated by a tubular member, the end member being partially hollow with a recess which receives an electrical heating element coupled by conductors which extend back through the tubular member and hanlde to an electrical cord. The knife is secured to the exterior of the end member so as to be heated by the heating element therewithin.
There is a serious and hazardous disadvantage to such a structural arrangement since the entire end member is heated by its enclosed heating element. On the other hand this type of arrangement has been practically dictated (up to the time of the present invention) by the necessity of maintaining a relatively small knife with a thin profile configuration with precludes the possibility of forming the knife over any sort of heating element -- hence the prior art requirement for heat transfer arrangements of one sort or another.